btrfs-progs/common/string-utils.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include "kerncompat.h"
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include "common/string-utils.h"
#include "common/messages.h"

int string_is_numerical(const char *str)
{
	if (!str)
		return 0;
	if (!(*str >= '0' && *str <= '9'))
		return 0;
	while (*str >= '0' && *str <= '9')
		str++;
	if (*str != '\0')
		return 0;
	return 1;
}

int string_has_prefix(const char *str, const char *prefix)
{
	for (; ; str++, prefix++)
		if (!*prefix)
			return 0;
		else if (*str != *prefix)
			return (unsigned char)*prefix - (unsigned char)*str;
}

/*
 * This function should be only used when parsing command arg, it won't return
 * error to its caller and rather exit directly just like usage().
 */
u64 arg_strtou64(const char *str)
{
	u64 value;
	char *ptr_parse_end = NULL;

	value = strtoull(str, &ptr_parse_end, 0);
	if (ptr_parse_end && *ptr_parse_end != '\0') {
		error("%s is not a valid numeric value", str);
		exit(1);
	}

	/*
	 * if we pass a negative number to strtoull, it will return an
	 * unexpected number to us, so let's do the check ourselves.
	 */
	if (str[0] == '-') {
		error("%s: negative value is invalid", str);
		exit(1);
	}
	if (value == ULLONG_MAX) {
		error("%s is too large", str);
		exit(1);
	}
	return value;
}